1. Field of the Invention
This invention relates to couplings, and particularly to, no-hub couplings for joining segments of pipes.
2. Description of the Related Art
Currently there exist a number of different pipe couplers, and one common form of which is referred to as a “no-hub coupling.” Prior to the creation of the “no-hub coupling,” cast iron pipes were joined together at a union called a hub, wherein two pipe segments of different diameters where joined at the hub, and the connection was sealed using such things as oakum and melted lead. The no-hub coupling 20 (FIGS. 1 and 2) was later introduced as a mechanically interlocking connection between two pipe segments 22 and 24 wherein a shield 26 covering an elastomeric gasket 28 is used to connect the two pipe segments 22 and 24. In a typical no-hub coupling a shield 26 with a plurality of corrugations 30 parallel to the axis of the pipe is provided, with two or four clamping bands 32 covering the shield 26, and an elastomeric gasket 28 covered by the shield 26, which makes sealing contact with the pipe segments 22 and 24. Various improvements and modifications to the early no-hub couplings that were designed as early as in the 1960's have been attempted. Examples of such designs may be found in U.S. Pat. No. 5,431,458.
However, one drawback of existing no-hub coupling devices is that with the typical no-hub coupling, the coupling shield is in the shape of a cylinder or tube with two open ends wherein the two pipe segments that are to be joined can only be inserted from the two ends of the shield, and then the clamps would have to be tightened. This makes the process of insertion of the pipe segments to be time consuming, cumbersome, and require some force. In addition, the process of tightening of the clamps of the shield over the pipe segments is not very simple, given that the pipe segments are not easy to hold and may slip out before the clamps are completely tightened and closed.
In view of the foregoing, a pipe coupling device is needed that is simple to use, place, hold and tighten over two pipe segments, is able to effectively grip and hold the joining pipe segments together without sliding, and would be relatively inexpensive to manufacture. The present invention fulfills these and other needs.